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  <div class="section" id="module-multifile">
<h1>19.10. <tt class="xref docutils literal"><span class="pre">multifile</span></tt> &#8212; Support for files containing distinct parts<a class="headerlink" href="#module-multifile" title="Permalink to this headline">¶</a></h1>
<p>
<span class="versionmodified">Deprecated since version 2.5: </span>The <a title="Package supporting the parsing, manipulating, and generating email messages, including MIME documents." class="reference external" href="email.html#module-email"><tt class="xref docutils literal"><span class="pre">email</span></tt></a> package should be used in preference to the <tt class="xref docutils literal"><span class="pre">multifile</span></tt>
module. This module is present only to maintain backward compatibility.</p>
<p>The <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> object enables you to treat sections of a text file as
file-like input objects, with <tt class="docutils literal"><span class="pre">''</span></tt> being returned by <tt class="xref docutils literal"><span class="pre">readline()</span></tt> when a
given delimiter pattern is encountered.  The defaults of this class are designed
to make it useful for parsing MIME multipart messages, but by subclassing it and
overriding methods  it can be easily adapted for more general use.</p>
<dl class="class">
<dt id="multifile.MultiFile">
<em class="property">
class </em><tt class="descclassname">multifile.</tt><tt class="descname">MultiFile</tt><big>(</big><em>fp</em><span class="optional">[</span>, <em>seekable</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#multifile.MultiFile" title="Permalink to this definition">¶</a></dt>
<dd><p>Create a multi-file.  You must instantiate this class with an input object
argument for the <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> instance to get lines from, such as a file
object returned by <a title="open" class="reference external" href="functions.html#open"><tt class="xref docutils literal"><span class="pre">open()</span></tt></a>.</p>
<p><a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> only ever looks at the input object&#8217;s <a title="multifile.MultiFile.readline" class="reference internal" href="#multifile.MultiFile.readline"><tt class="xref docutils literal"><span class="pre">readline()</span></tt></a>,
<a title="multifile.MultiFile.seek" class="reference internal" href="#multifile.MultiFile.seek"><tt class="xref docutils literal"><span class="pre">seek()</span></tt></a> and <a title="multifile.MultiFile.tell" class="reference internal" href="#multifile.MultiFile.tell"><tt class="xref docutils literal"><span class="pre">tell()</span></tt></a> methods, and the latter two are only needed if you
want random access to the individual MIME parts. To use <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> on a
non-seekable stream object, set the optional <em>seekable</em> argument to false; this
will prevent using the input object&#8217;s <a title="multifile.MultiFile.seek" class="reference internal" href="#multifile.MultiFile.seek"><tt class="xref docutils literal"><span class="pre">seek()</span></tt></a> and <a title="multifile.MultiFile.tell" class="reference internal" href="#multifile.MultiFile.tell"><tt class="xref docutils literal"><span class="pre">tell()</span></tt></a> methods.</p>
</dd></dl>

<p>It will be useful to know that in <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a>&#8216;s view of the world, text
is composed of three kinds of lines: data, section-dividers, and end-markers.
MultiFile is designed to support parsing of messages that may have multiple
nested message parts, each with its own pattern for section-divider and
end-marker lines.</p>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt>Module <a title="Package supporting the parsing, manipulating, and generating email messages, including MIME documents." class="reference external" href="email.html#module-email"><tt class="xref docutils literal"><span class="pre">email</span></tt></a></dt>
<dd>Comprehensive email handling package; supersedes the <tt class="xref docutils literal"><span class="pre">multifile</span></tt> module.</dd>
</dl>
</div>
<div class="section" id="multifile-objects">
<span id="id1"></span><h2>19.10.1. MultiFile Objects<a class="headerlink" href="#multifile-objects" title="Permalink to this headline">¶</a></h2>
<p>A <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> instance has the following methods:</p>
<dl class="method">
<dt id="multifile.MultiFile.readline">
<tt class="descclassname">MultiFile.</tt><tt class="descname">readline</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.readline" title="Permalink to this definition">¶</a></dt>
<dd>Read a line.  If the line is data (not a section-divider or end-marker or real
EOF) return it.  If the line matches the most-recently-stacked boundary, return
<tt class="docutils literal"><span class="pre">''</span></tt> and set <tt class="docutils literal"><span class="pre">self.last</span></tt> to 1 or 0 according as the match is or is not an
end-marker.  If the line matches any other stacked boundary, raise an error.  On
encountering end-of-file on the underlying stream object, the method raises
<tt class="xref docutils literal"><span class="pre">Error</span></tt> unless all boundaries have been popped.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.readlines">
<tt class="descclassname">MultiFile.</tt><tt class="descname">readlines</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.readlines" title="Permalink to this definition">¶</a></dt>
<dd>Return all lines remaining in this part as a list of strings.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.read">
<tt class="descclassname">MultiFile.</tt><tt class="descname">read</tt><big>(</big><big>)</big><a class="headerlink" href="#multifile.MultiFile.read" title="Permalink to this definition">¶</a></dt>
<dd>Read all lines, up to the next section.  Return them as a single (multiline)
string.  Note that this doesn&#8217;t take a size argument!</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.seek">
<tt class="descclassname">MultiFile.</tt><tt class="descname">seek</tt><big>(</big><em>pos</em><span class="optional">[</span>, <em>whence</em><span class="optional">]</span><big>)</big><a class="headerlink" href="#multifile.MultiFile.seek" title="Permalink to this definition">¶</a></dt>
<dd>Seek.  Seek indices are relative to the start of the current section. The <em>pos</em>
and <em>whence</em> arguments are interpreted as for a file seek.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.tell">
<tt class="descclassname">MultiFile.</tt><tt class="descname">tell</tt><big>(</big><big>)</big><a class="headerlink" href="#multifile.MultiFile.tell" title="Permalink to this definition">¶</a></dt>
<dd>Return the file position relative to the start of the current section.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.next">
<tt class="descclassname">MultiFile.</tt><tt class="descname">next</tt><big>(</big><big>)</big><a class="headerlink" href="#multifile.MultiFile.next" title="Permalink to this definition">¶</a></dt>
<dd>Skip lines to the next section (that is, read lines until a section-divider or
end-marker has been consumed).  Return true if there is such a section, false if
an end-marker is seen.  Re-enable the most-recently-pushed boundary.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.is_data">
<tt class="descclassname">MultiFile.</tt><tt class="descname">is_data</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.is_data" title="Permalink to this definition">¶</a></dt>
<dd><p>Return true if <em>str</em> is data and false if it might be a section boundary.  As
written, it tests for a prefix other than <tt class="docutils literal"><span class="pre">'-</span></tt><tt class="docutils literal"><span class="pre">-'</span></tt> at start of line (which
all MIME boundaries have) but it is declared so it can be overridden in derived
classes.</p>
<p>Note that this test is used intended as a fast guard for the real boundary
tests; if it always returns false it will merely slow processing, not cause it
to fail.</p>
</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.push">
<tt class="descclassname">MultiFile.</tt><tt class="descname">push</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.push" title="Permalink to this definition">¶</a></dt>
<dd><p>Push a boundary string.  When a decorated version of this boundary  is found as
an input line, it will be interpreted as a section-divider  or end-marker
(depending on the decoration, see <span class="target" id="index-420"></span><a class="reference external" href="http://tools.ietf.org/html/rfc2045.html"><strong>RFC 2045</strong></a>).  All subsequent reads will
return the empty string to indicate end-of-file, until a call to <a title="multifile.MultiFile.pop" class="reference internal" href="#multifile.MultiFile.pop"><tt class="xref docutils literal"><span class="pre">pop()</span></tt></a>
removes the boundary a or <a title="next" class="reference external" href="functions.html#next"><tt class="xref docutils literal"><span class="pre">next()</span></tt></a> call reenables it.</p>
<p>It is possible to push more than one boundary.  Encountering the
most-recently-pushed boundary will return EOF; encountering any other
boundary will raise an error.</p>
</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.pop">
<tt class="descclassname">MultiFile.</tt><tt class="descname">pop</tt><big>(</big><big>)</big><a class="headerlink" href="#multifile.MultiFile.pop" title="Permalink to this definition">¶</a></dt>
<dd>Pop a section boundary.  This boundary will no longer be interpreted as EOF.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.section_divider">
<tt class="descclassname">MultiFile.</tt><tt class="descname">section_divider</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.section_divider" title="Permalink to this definition">¶</a></dt>
<dd>Turn a boundary into a section-divider line.  By default, this method
prepends <tt class="docutils literal"><span class="pre">'--'</span></tt> (which MIME section boundaries have) but it is declared so
it can be overridden in derived classes.  This method need not append LF or
CR-LF, as comparison with the result ignores trailing whitespace.</dd></dl>

<dl class="method">
<dt id="multifile.MultiFile.end_marker">
<tt class="descclassname">MultiFile.</tt><tt class="descname">end_marker</tt><big>(</big><em>str</em><big>)</big><a class="headerlink" href="#multifile.MultiFile.end_marker" title="Permalink to this definition">¶</a></dt>
<dd>Turn a boundary string into an end-marker line.  By default, this method
prepends <tt class="docutils literal"><span class="pre">'--'</span></tt> and appends <tt class="docutils literal"><span class="pre">'--'</span></tt> (like a MIME-multipart end-of-message
marker) but it is declared so it can be overridden in derived classes.  This
method need not append LF or CR-LF, as comparison with the result ignores
trailing whitespace.</dd></dl>

<p>Finally, <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> instances have two public instance variables:</p>
<dl class="attribute">
<dt id="multifile.MultiFile.level">
<tt class="descclassname">MultiFile.</tt><tt class="descname">level</tt><a class="headerlink" href="#multifile.MultiFile.level" title="Permalink to this definition">¶</a></dt>
<dd>Nesting depth of the current part.</dd></dl>

<dl class="attribute">
<dt id="multifile.MultiFile.last">
<tt class="descclassname">MultiFile.</tt><tt class="descname">last</tt><a class="headerlink" href="#multifile.MultiFile.last" title="Permalink to this definition">¶</a></dt>
<dd>True if the last end-of-file was for an end-of-message marker.</dd></dl>

</div>
<div class="section" id="multifile-example">
<span id="id2"></span><h2>19.10.2. <a title="multifile.MultiFile" class="reference internal" href="#multifile.MultiFile"><tt class="xref docutils literal"><span class="pre">MultiFile</span></tt></a> Example<a class="headerlink" href="#multifile-example" title="Permalink to this headline">¶</a></h2>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">mimetools</span>
<span class="kn">import</span> <span class="nn">multifile</span>
<span class="kn">import</span> <span class="nn">StringIO</span>

<span class="k">def</span> <span class="nf">extract_mime_part_matching</span><span class="p">(</span><span class="n">stream</span><span class="p">,</span> <span class="n">mimetype</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;Return the first element in a multipart MIME message on stream</span>
<span class="sd">    matching mimetype.&quot;&quot;&quot;</span>

    <span class="n">msg</span> <span class="o">=</span> <span class="n">mimetools</span><span class="o">.</span><span class="n">Message</span><span class="p">(</span><span class="n">stream</span><span class="p">)</span>
    <span class="n">msgtype</span> <span class="o">=</span> <span class="n">msg</span><span class="o">.</span><span class="n">gettype</span><span class="p">()</span>
    <span class="n">params</span> <span class="o">=</span> <span class="n">msg</span><span class="o">.</span><span class="n">getplist</span><span class="p">()</span>

    <span class="n">data</span> <span class="o">=</span> <span class="n">StringIO</span><span class="o">.</span><span class="n">StringIO</span><span class="p">()</span>
    <span class="k">if</span> <span class="n">msgtype</span><span class="p">[:</span><span class="mf">10</span><span class="p">]</span> <span class="o">==</span> <span class="s">&quot;multipart/&quot;</span><span class="p">:</span>

        <span class="nb">file</span> <span class="o">=</span> <span class="n">multifile</span><span class="o">.</span><span class="n">MultiFile</span><span class="p">(</span><span class="n">stream</span><span class="p">)</span>
        <span class="nb">file</span><span class="o">.</span><span class="n">push</span><span class="p">(</span><span class="n">msg</span><span class="o">.</span><span class="n">getparam</span><span class="p">(</span><span class="s">&quot;boundary&quot;</span><span class="p">))</span>
        <span class="k">while</span> <span class="nb">file</span><span class="o">.</span><span class="n">next</span><span class="p">():</span>
            <span class="n">submsg</span> <span class="o">=</span> <span class="n">mimetools</span><span class="o">.</span><span class="n">Message</span><span class="p">(</span><span class="nb">file</span><span class="p">)</span>
            <span class="k">try</span><span class="p">:</span>
                <span class="n">data</span> <span class="o">=</span> <span class="n">StringIO</span><span class="o">.</span><span class="n">StringIO</span><span class="p">()</span>
                <span class="n">mimetools</span><span class="o">.</span><span class="n">decode</span><span class="p">(</span><span class="nb">file</span><span class="p">,</span> <span class="n">data</span><span class="p">,</span> <span class="n">submsg</span><span class="o">.</span><span class="n">getencoding</span><span class="p">())</span>
            <span class="k">except</span> <span class="ne">ValueError</span><span class="p">:</span>
                <span class="k">continue</span>
            <span class="k">if</span> <span class="n">submsg</span><span class="o">.</span><span class="n">gettype</span><span class="p">()</span> <span class="o">==</span> <span class="n">mimetype</span><span class="p">:</span>
                <span class="k">break</span>
        <span class="nb">file</span><span class="o">.</span><span class="n">pop</span><span class="p">()</span>
    <span class="k">return</span> <span class="n">data</span><span class="o">.</span><span class="n">getvalue</span><span class="p">()</span>
</pre></div>
</div>
</div>
</div>


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            <ul>
<li><a class="reference external" href="">19.10. <tt class="docutils literal"><span class="pre">multifile</span></tt> &#8212; Support for files containing distinct parts</a><ul>
<li><a class="reference external" href="#multifile-objects">19.10.1. MultiFile Objects</a></li>
<li><a class="reference external" href="#multifile-example">19.10.2. <tt class="docutils literal"><span class="pre">MultiFile</span></tt> Example</a></li>
</ul>
</li>
</ul>

            <h4>Previous topic</h4>
            <p class="topless"><a href="mimify.html"
                                  title="previous chapter">19.9. <tt class="docutils literal docutils literal docutils literal"><span class="pre">mimify</span></tt> &#8212; MIME processing of mail messages</a></p>
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